Variable Thermal Resistance Device for Vehicular Seats

ABSTRACT

A seating assembly comprising: a frame having an opening; a support surface spanning the opening in the frame; a variable thermal resistance device that opposes the support surface when the variable thermal resistance device is in a closed state in which airflow is obstructed, the variable thermal resistance device being movable from the closed state to an open state in which airflow is not obstructed and from the open state to the closed state; and an actuator coupled to the variable thermal resistance device. The actuator is operable to actuate movement of the variable thermal resistance device between the open and closed states.

RELATED PATENT APPLICATION

This application is a divisional of and claims priority from U.S. patentapplication Ser. No. 13/779,242 filed on Feb. 27, 2013.

BACKGROUND

This disclosure generally relates to passenger seats for vehicles. Inparticular, this disclosure relates to passenger seats for aircraft.

During hot day ground conditions at the gate, an airplane's airconditioning system is typically not powered, resulting in hightemperatures in the passenger cabin. When the passengers or crew sit,the seat increases their clothing resistance, making them even warmer.This results in hot, sweaty, uncomfortable seated passengers and crewwhile the airplane is on the ground.

The current solution for hot conditions in a conventional aircraftpassenger seat is to provide passenger and crew with personal airoutlets (commonly called “gaspers”). Gaspers increase heat transfer andevaporation from (i.e., cool) the exposed surfaces of a seated person'sbody, but they cannot provide a cooling effect to surfaces blocked byseat cushions and fabric. It may also be the case that some passengersdeparting from an airport on a hot day find that the airflow from thegaspers is insufficient to eliminate discomfort while the aircraftremains at the gate.

A new generation of lightweight passenger seats use a mesh fabricmaterial or webbing instead of solid cushions. If the pores in the meshmaterial are left open, this ventilates the seated person's back andthighs, resulting in a cooler sensation during hot-day groundconditions. But a seat made in this manner would over-ventilate theseated person at cruise altitude, resulting in cold, chilly,uncomfortable seated passengers and crew. The current solution for coldconditions in a mesh seat is to cover the seat face with leather, whichunfortunately also eliminates the advantage the mesh seat has for hotday conditions.

It would be desirable to modify existing passenger seats so that thetemperature-reducing effect of gaspers could be supplemented when avehicle is on the ground during hot-day conditions.

SUMMARY

One aspect of the subject matter disclosed in detail hereinafter is aseating assembly comprising: a frame having an opening; a supportsurface spanning the opening in the frame; a variable thermal resistancedevice that opposes the support surface when the variable thermalresistance device is in a closed state in which airflow is obstructed,the variable thermal resistance device being movable from the closedstate to an open state in which airflow is not obstructed and from theopen state to the closed state; and an actuator coupled to the variablethermal resistance device. The actuator is operable to actuate movementof the variable thermal resistance device between the open and closedstates. The support surface can be air-permeable or non-porous.Optionally, one or both of the support surface and the variable thermalresistance device comprises material having high thermal conductivity.

Another aspect of the disclosed subject matter is a seating assemblycomprising: a frame having an opening; a support surface spanning theopening in the frame; a variable thermal resistance device that opposesthe support surface when the variable thermal resistance device is in aclosed state in which airflow is obstructed, the variable thermalresistance device being movable from the closed state to an open statein which airflow is not obstructed and from the open state to the closedstate; and an actuator coupled to the variable thermal resistancedevice, the actuator being operable to actuate movement of the variablethermal resistance device between the open and closed states. One orboth of the support surface and the variable thermal resistance devicecomprises material having high thermal conductivity of at least 40W/m-^(o)K.

In accordance with one embodiment disclosed in detail below, a seatingassembly comprises: a frame having an opening; a suspension fabric undertension and spanning the opening in the frame; a multiplicity of louversthat are movable between a closed state in which the louvers obstructairflow toward the suspension fabric and an open state in which thelouvers do not obstruct airflow toward the suspension fabric; and arotatable cylinder coupled to the louvers by at least one cord. Thelouvers move from the closed state to the open state when the rotatablecylinder is rotated in one direction, and move from the open state tothe closed state when the rotatable cylinder is rotated in anotherdirection opposite to the one direction. The louvers may comprisemagnets or hook-and-loop fasteners arranged to hold the louvers in theclosed state. Each louver may comprise a foam core wrapped in fabricwhich is coupled to the suspension fabric.

Other aspects of the improved passenger seat designs are disclosed andclaimed below.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments will be hereinafter described with reference todrawings, which show some but not all components of various passengerseat assemblies.

FIG. 1 is a diagram showing a front isometric view of an aircraftseating layout for a known embodiment of a passenger seat assembly.

FIG. 2 is a diagram showing a rear isometric view of the embodiment of apassenger seat assembly shown in FIG. 1.

FIG. 3 is a diagram showing a front isometric view of a one-piecestructural frame incorporated in the passenger seat assembly shown inFIG. 1.

FIG. 4 is a diagram showing a front isometric view of a one-piecesupport frame incorporated in the passenger seat assembly shown in FIG.1.

FIG. 5 is a diagram showing a front isometric view of a comfort frameassembly which incorporates the support frame shown in FIG. 4.

FIG. 6 is a diagram showing a cross-sectional view of a comfort frameassembly comprising suspension fabric.

FIGS. 7 and 8 are diagrams showing components of a modified passengerseat having actuatable louvers for selectively opening (see FIG. 7) andclosing (see FIG. 8) an air-permeable layer that is in contact with thebody of a seated passenger.

FIG. 9 is a diagram illustrating the principle of operation of thelouver-equipped passenger seat diagrammed in FIGS. 7 and 8.

FIGS. 10A and 10B are diagrams showing top views of a portion of alouver-equipped passenger seat in which the support surface is anon-porous material having high thermal conductivity. The louvers areshown in their fully closed (see FIG. 10A) and fully open (see FIG. 10B)states.

FIGS. 11A and 11B are diagrams showing an alternative embodiment inwhich airflow to and/or heat transfer from a passenger support surface(either air-permeable or non-porous) can be controlled by a non-porousmovable surface.

FIG. 12 is a diagram showing a sectional view of a portion of apassenger seat equipped with a variable thermal resistance device in theform of a stretchable sheet whose porosity increases when the sheet isstretched in accordance with an alternative embodiment.

FIG. 13 is a diagram showing a plan view of a stretchable slitted sheetwhich can be used in the embodiment depicted in FIG. 12.

FIG. 14 is a diagram showing the principle of operation of a variablethermal resistance comprising a fabric sling which, when under tension(as shown in FIG. 14), contacts a suspension fabric supporting apassenger to obstruct airflow through the suspension fabric and, whenslack (not shown in FIG. 14), does not obstruct airflow through thesuspension fabric.

FIG. 15 is a block diagram showing components of an electronicallycontrolled system for varying the thermal resistance of passenger seatsof a vehicle.

FIGS. 16A and 16B are diagrams showing an alternative embodiment havingvents which can be opened or closed to adjust the temperature inside aspace behind and/or under the seated passenger.

Reference will hereinafter be made to the drawings in which similarelements in different drawings bear the same reference numerals.

DETAILED DESCRIPTION

The subject matter disclosed herein is directed to passenger seats thatcan be adjusted to provide thermal comfort to seated passengers in hotand cold conditions. These improved passenger seats provide greaterthermal comfort to seated persons during hot-day ground conditions bydecreasing the effective insulation value of the seated person'sclothing. During cold conditions, this effect can be negated, increasingthe effective insulation value of the seated person's clothing.

The variable thermal resistance passenger seats disclosed in detailhereinafter are intended to supplement (rather than replace) gaspers, byproviding cooling to the surfaces which support the seated passenger'sbody, which can become hot and sweaty in hot-day conditions. Theproposed seat provides this cooling function only as desired, such asduring hot day conditions, and not during cold cruise conditions, whenthe typical passenger desires enhanced insulation.

The disclosed variable thermal resistance passenger seats provideenhanced comfort under circumstances when the normal cooling system isnot powered, such as during loading and unloading of passengers, andprior to start of the auxiliary power unit. These variable thermalresistance passenger seats also provide enhanced comfort during delayeddepartures, especially for equipment failures, when the normalventilation and gasper systems might not be powered. The improved seatdesigns disclosed herein improve hot day ground thermal performance withminimal or zero weight gain versus mesh fabric seats, or a substantialweight reduction versus conventional seats.

Various embodiments of passenger seats provided with systems that enablethe passenger to vary the thermal resistance of his seat will now bedescribed. More specifically, variable thermal resistance devices inaccordance with various embodiments will be described in the context ofpassenger seats on an aircraft. However, the variable thermal resistancedevices to be disclosed also have application in passenger seats onother transport vehicles, such as buses and trains, or on furniture,such as office furniture.

In accordance with various embodiments, a variable thermal resistancedevice can be incorporated in passenger seat assemblies having eitherair-permeable passenger support surfaces (e.g., suspension fabric), inwhich case the variable thermal resistance device either obstructs ordoes not obstruct airflow through the air-permeable material, orair-impermeable passenger support surfaces (e.g., closed-cell foam or acontinuous sheet of strong, stretchable plastic material), in which casethe variable thermal resistance device either obstructs or does notobstruct airflow across the back surface of the air-impermeablematerial. In either case, the passenger support surfaces may beincorporated in passenger seat assemblies of the type shown in FIGS.1-4.

FIG. 1 is a front isometric view of a portion of an aircraft seatinglayout 100 using an embodiment of a passenger seat assembly 102 (shownin detail in the rear isometric view of FIG. 2). Seat assemblies 102 aresuitable for use as passenger seats in an aircraft, e.g., as a row in acommercial aircraft. Seat assemblies 102 can be coupled to anappropriate and suitable airframe structure of the aircraft, such as thefloor, one or more sidewalls, support beams, or the like. In theembodiment depicted in FIG. 1, seat assemblies 102 are coupled to seattracks 104, which provide a mounting interface between seat assemblies102 and the airframe structure of the aircraft.

Although each seat assembly 102 is depicted as a triple seat assembly,the concepts, techniques, features, and technologies described hereincan be extended to any practical seat configuration, such as a doubleseat, a quad seat, a single seat, or a seat configured to accommodateany number of passengers, limited only by practical size restrictions,structural material properties, and aircraft interior configurationregulations.

Referring to FIG. 2, seat assembly 102 includes two primary modularcomponents: a structural frame 106 and a plurality of comfort frameassemblies 108, which are coupled to and supported by structural frame106 when seat assembly 102 is deployed. This modular approach assignsthe two main functions of a passenger seat (comfortably support thepassenger and restrain the passenger) to comfort frame assemblies 108and structural frame 106, respectively. In this embodiment, seatassembly 102 has three comfort frame assemblies 108—one for eachpassenger seat location. Comfort frame assemblies 108 may be virtuallyidentical in a commercial aircraft deployment.

A modular passenger seat assembly as described herein may also includeheadrests 134 and/or tray tables 136 (see FIG. 2). Tray tables 136 maybe designed for storage in the back of the support frames of the comfortframe assemblies 108. The back of the structural frame 106 may includeappropriately sized openings formed therein to accommodate the loweringof tray tables 136.

FIG. 3 is a front isometric view of a structural frame 106 installed onseat tracks 104. Structural frame 106 is suitably configured to supportat least one passenger (three passengers in the illustrated embodiment),and to transfer dynamic loads associated with the passenger(s) to anairframe structure of the aircraft. For example, structural frame 106can be designed to facilitate the transfer of loads from seat assembly102 to seat tracks 104, the floor of the aircraft, the sidewalls of theaircraft, or other structural components of the aircraft. Structuralframe 106 is fabricated as a one-piece component. Structural frame 106may be designed and fabricated to be a monocoque construction, i.e.,such that it absorbs and/or transfers most of the loads and stresses towhich seat assembly 102 is subjected. In certain embodiments, structuralframe 106 is a one-piece composite construction, for example, a moldedcomposite component.

Still referring to FIG. 3, structural frame 106 generally includes Nseat subframes 110 corresponding to N passenger seat locations (in theillustrated embodiment, N=3). Considering the one-piece construction ofstructural frame 106, seat subframes 110 represent integral features ofstructural frame 106. Structural frame 106 has an upper end 112, a lowerend 114, and an aircraft mounting structure 116 formed therein. Aircraftmounting structure 116, which is located at lower end 114, is suitablyconfigured to accommodate coupling to the airframe structure of theaircraft. Aircraft mounting structure 116 may, for example, be designedfor compatibility with seat tracks 104 that are integrated into thefloor of the aircraft. For this embodiment, aircraft mounting structure116 is realized as a number of mounting “feet” or “rails” that cooperatewith seat tracks 104 and/or accommodate fasteners or coupling mechanismsthat are utilized to attach structural frame 106 to seat tracks 104.

Lower end 114 generally represents the base of structural frame 106, andupper end 112 generally represents the seatback portion of structuralframe 106. Structural frame 106 may also include the followingintegrated features formed therein: a number of support legs 118; anumber of back support elements 120; a lower back crossbeam 122; and anupper back crossbeam 124. As depicted in the figures, aircraft mountingstructure 116 is connected to support legs 118, which are connected toback support elements 120. Back support elements 120 extend upwardly andin a slightly angled orientation from support legs 118. In thisembodiment, two of the support legs 118 and two of the back supportelements 120 are common to two of the seat subframes 110. On the otherhand, the outermost support legs 118 and the outermost back supportelements 120 are utilized for only one seat subframe 110. Lower backcrossbeam 122 and upper back crossbeam 124 are connected to the backsupport elements 120. Structural frame 106 may also include armrestcoupling features 126 (see FIG. 3) for the attachment of armrests 128(see FIG. 2) to seat assembly 102, and seat belt coupling features 130(see FIG. 3) for the attachment of passenger seat belts to seat assembly102.

Referring again to FIG. 2, seat assembly 102 comprises multiple comfortframe assemblies 108, which respectively correspond to the seatsubframes 110. Each comfort frame assembly 108 is suitably configured tocooperate with structural frame 106 to accommodate movement of comfortframe assembly 108 relative to structural frame 106. In accordance withsome embodiments, comfort frame assembly 108 can pivot (recline)independently relative to structural frame 106. Moreover, structuralframe 106 itself is designed to be a “fixed” support component forcomfort frame assemblies 108. Thus, comfort frame assemblies 108 movewithin the fixed confines of structural frame 106.

Each comfort frame assembly 108 is fabricated from two main components:a support frame (item 200 shown in FIG. 4) and a fabric carrier (item218 shown in FIG. 5) coupled to the support frame 106, where the fabriccarrier 218 defines a seating surface of the respective comfort frameassembly 108.

As seen in FIG. 4, support frame 200 can be fabricated as a one-piececomponent. In certain embodiments, support frame 200 is a lightweightmolded composite component. An embodiment of support frame 200 may befabricated using any number of materials and compositions, including,without limitation, the materials and compositions described above inthe context of structural frame 106. In addition, support frame 200 isergonomically shaped and contoured according to the desired seatconfiguration. The particular embodiment depicted in FIG. 4 comprises alower edge 206, a lower leg frame section 208 connected to lower edge206, a seating frame section 210 connected to lower leg frame section208, and a back section 212 connected to seating frame section 210.These features are formed as integral features of one-piece supportframe 200. Back section 212 is preferably a solid panel section havingan opening 202. Lower leg frame section 208 comprises an outer framethat defines an opening 214, and seating frame section 210 comprises anouter frame that defines an opening 216. Openings 202/214/216 arecovered with material in the finished assembly. These openings202/214/216 provide ventilation for increased passenger comfort. Eachcomfort frame assembly 108 can be suitably configured to reduce pressurepoints and to provide passive temperature control due to air circulationaround the passenger.

FIG. 5 is an isometric view of a comfort frame assembly 108 inaccordance with an alternative embodiment. This comfort frame assembly108 comprises a fabric carrier 218 coupled to a support frame 200. Thefabric carrier 218 comprises a strong, stretchable suspension fabric220. The perimeter of the suspension fabric 220 is attached to a fabriccarrier ring (not visible in FIG. 5), which is attached to support frame200. The suspension fabric 220 primarily serves to support the weight ofthe occupant.

As best seen in the sectional view of FIG. 6, fabric carrier 218 maycomprise a fabric carrier ring 228. The fabric carrier ring 228 mayroughly correspond to the outer edge of support frame 200 and hasopenings which overlap the openings formed in support frame 200 (e.g.,openings 202/214 seen in FIG. 4). In the embodiment shown in FIG. 6,support frame 200 has a generally L-shaped cross section in the areasproximate to an opening.

Fabric carrier ring 228 may be molded from a variety of suitablethermoplastic materials or the like. Fabric carrier 218 may bemanufactured by encapsulating at least a portion of suspension fabric220 in fabric carrier ring 228. For example, the margin along theperimeter of the suspension fabric 220 can be encapsulated in fabriccarrier ring 228 such that it spans the opening formed in fabric carrierring 228. Fabric carrier 218 can be attached to support frame 200 usingany suitable means, including without limitation: fasteners, adhesive,snaps, clips, bonding, or the like. For example, fabric carrier ring 228may include prongs, barbs, or other features 236 that enable fabriccarrier 218 to be secured to support frame 200 during assembly.

Returning to FIG. 2, the modular passenger seat assembly 102 may furthercomprise a suitably configured pivot mechanism that accommodatespivoting (or other modes of travel) of the comfort frame assembly 108relative to the structural frame 106. The pivot mechanism may alsoaccommodate features that permit the installation and removal of thecomfort frame assembly 108 from the structural frame 106. The pivotmechanism may be configured to accommodate pivoting of comfort frameassemblies 108 about an axis that is located near lower end 114 ofstructural frame 106. For this embodiment, lower end 114 roughlycorresponds to a passenger ankle or foot location, and the pivot axiscorresponds to a rod 132 or other hinge element of seat assembly 102.For this embodiment, the pivot mechanism includes rod 132 (seen in FIGS.2 and 3) and tube sections 238 formed in support frame 200 near loweredge 206 (seen in FIGS. 4 and 5). Tube sections 238 are pivotallycoupled to rod 132, which is in turn secured to lower end 114 ofstructural frame 106. Seat assembly 102 may include actuators, springs,control mechanisms, mechanical travel stops, and other features thatallow the passenger to adjust the position of comfort frame assembly 108relative to structural frame 106.

In accordance with the teachings herein, each aircraft passenger seatdescribed above can be modified to include a respective apparatus forincreasing the thermal comfort of seated passengers in hot and coldconditions. Such an apparatus is referred to herein as a “variablethermal resistance device”. For example, each aircraft passenger seatcan be modified by incorporating a first variable thermal resistancedevice underneath the seat and a second variable thermal resistancedevice behind the seat. Each variable thermal resistance device can beactuated to change from a closed state to an open state (in order tocool the passenger) or from an open state to a closed state (in order towarm the passenger). A variable thermal resistance device of any one ofthe types disclosed hereinafter provides greater thermal comfort toseated persons during hot-day ground conditions by decreasing theeffective insulation value of the seated person's clothing. Duringcold-day conditions at cruise, this effect can be negated, increasingthe effective insulation value of the seated person's clothing.

Clothing thermal resistance is measured in “clo” units. (See “ASHRAEFundamentals Handbook” or any guide on thermal comfort for guidance on“clo” units.) A person in a temperate climate (e.g., Seattle) typicallywears clothing having a thermal resistance about 0.7 clo. Sitting on aconventional aircraft passenger seat adds roughly 0.15 clo of thermalinsulation, equivalent to putting on a sweater vest. Sitting on a meshfabric, webbed, or ventilated seat squeezes the air out of a person'sclothing without adding any significant thermal resistance of its own.This reduces a person's thermal insulation by roughly 0.15 clo, which isequivalent to removing a short-sleeved shirt.

Variable thermal resistance devices will be disclosed hereinafter whichcan passively subtract at least 0.15 clo to enhance comfort in hotconditions, or add at least 0.15 clo to enhance comfort in coldconditions, without the use of fans or other active cooling devices. Avariety of different configurations will be described hereinafter forattaining the desired effect, but all versions have either a porous(i.e., air-permeable) or air-impermeable layer supporting the seatedperson combined with some mechanism for obstructing ventilation or heattransfer through or across the back surface of the supporting layer.

FIGS. 7 and 8 show components of a modified passenger seat havingactuatable louvers 16 for selectively opening (see FIG. 7) and closing(see FIG. 8) openings or pores of an air-permeable suspension fabric 12under tension that is in contact with and supports a portion of theseated passenger's body. [As used herein, the term “louver” refers to apanel, fin or slat that is movable.] Suitable suspension fabric may takethe form of a woven or knitted fabric (for example, webbing or meshfabric) made of synthetic fibers. More specifically, the suspensionfabric 12 may be formed from a relatively tough, stretchable, andresilient material or combination of materials, such as DUPONT™DYMETROL® high-performance bi-component woven fabric (comprisingelastomeric DUPONT™ HYTREL® filaments and high-quality textile yarn),polyester, nylon, KEVLAR®, NOMEX®, or the like. The suspension fabric 12is attached to a fabric carrier ring (not shown in FIGS. 7 and 8) andspans an opening formed by portions of the seat frame (only portions 10a and 10 b of the seat frame are shown in FIGS. 7 and 8). Seats of thisdesign are significantly lighter in weight than conventional aircraftpassenger seats, and are also thinner, allowing more seats on anaircraft without compromising accessibility.

In accordance with the embodiment shown in FIGS. 7 and 8, the variablethermal resistance device comprises a row of louvers 16 having one edge18 which is attached (e.g., by stitching or fasteners) to the suspensionfabric 12 in a manner such that the louvers can rotate between positionswhich are respectively perpendicular and parallel to the mesh orweb-like fabric 12. The opening in the fabric carrier ring can becovered by a decorative back cover 12. The air in the airspace betweensuspension fabric 12 and back cover 14 flows easily through thesuspension fabric 12 when the louvers 16 are perpendicular thereto (seeFIG. 8), whereas air is constrained from flowing through the suspensionfabric 12 when the louvers 16 are placed parallel to the fabric (seeFIG. 8). The back cover 14 would hide the louvers from view and protectthem from tampering.

The system schematically depicted in FIGS. 7 and 8 further comprises anactuator (not shown in FIGS. 7 and 8) for closing the row of louvers bymoving them from the perpendicular state shown in FIG. 7 to the parallelstate shown in FIG. 8, and for opening the row of louvers by moving themfrom the parallel state shown in FIG. 8 to the perpendicular state shownin FIG. 7. The actuator can be operated either manual or automatic.

In accordance with one embodiment, the actuator comprises a series ofcords, wires, or strings to move the louvers 16 from one state to theother, and pulleys, loops, eyelets or guides to connect the cords, wiresor string to a manually operated actuating mechanism.

The principle of operation of a variable thermal resistance devicecomprising louvers actuated by cords is shown in FIG. 9, which shows asingle louver 16 connected to an actuator in the form of a rotatablecylinder 22, (e.g., a drum, spool, roll or tube) by means of a singlecord having two segments 20 a and 20 b. The point of the cord at whichcord segments 20 a and 20 b connect to each other is attached to themovable distal edge of the louver 16 at location 24. (Alternatively, twoseparate cords 20 a and 20 b could be used.) A terminal portion of cordsegment 20 a is wrapped in one direction around a first portion of therotatable cylinder 22, while a terminal portion of cord segment 20 b iswrapped in an opposite direction around a second portion of therotatable cylinder 22. Thus, when the rotatable cylinder 22 rotates inone direction, causing louver 16 to move from its closed position(indicated by dashed lines in FIG. 9) to its open position, anincreasing length of cord segment 20 a is wound onto the first portionof rotatable cylinder 22, while an increasing length of cord segment 20b is being unwound from the second portion of rotatable cylinder 22.Conversely, when the rotatable cylinder 22 rotates in the oppositedirection, causing the louver to move from its open position to itsclosed position, an increasing length of cord segment 20 a is unwoundfrom the first portion of rotatable cylinder 22 while an increasinglength of cord segment 20 b is being wound onto the second portion ofrotatable cylinder 22. Cord segments 20 a and 20 b should havesufficient slack that cord tension will not interfere with or impederotation of the louver and the accompanying displacement of its distaledge toward and away from the seat material during opening and closing.For the purpose of simplification, FIG. 9 shows cord segment 20 apassing over a first pulley 22 a and cord segment 20 b passing over asecond pulley 22 b. However, any number of pulleys can be utilizeddepending on the requirements of the respective paths to be followed bythe cord segments.

Multiple cords may be provided which wrap around the rotatable element22 at respective axial positions and which connect to each louver in arow at respective locations. For example, louvers in the form of slatsmay have two cords attached at upper and lower locations. Furthermore,although FIG. 9 shows the cord connected to only one louver, it shouldalso be understood that each cord can be attached to each louver of arow of louvers so that all louvers in a row open and close in unison. Inaddition, the array of louvers may comprise multiple rows, the height ofthe louvers being reduced so that they resemble tiles more than panels,fins or slats.

The rotatable cylinder 22 shown in FIG. 9 can be placed underneath thepassenger seat, but within reach of the seated passenger. One end of therotatable cylinder may be provided with a knob having a grooved ortextured surface to facilitate turning with one hand. Instead of a knob,the user interface can consist of a lever or any other suitable devicefor pulling the cords or strings by manual operation.

In accordance with one embodiment, each louver may comprise a firm foamcore wrapped inside soft, insulative fabric, for example, Polarfleece™.[Polarfleece™ is a soft napped insulating synthetic fabric made frompolyethylene terephthalate or other synthetic fibers.] Other types offabric may be substituted for the polar fleece; other substrates (e.g.,wood or composite material) may be substituted for the foam core. Panelscan be utilized instead of the louvers. The louvers may be attacheddirectly to the suspension fabric or to some other surface of the seatassembly. The louvers could be fitted with magnets or hook-and-loopfasteners such that when they are in the closed state, they seal airmovement more effectively.

The louvers could be rigid if they were segmented lengthwise. Forexample, several dozen postage stamp-sized tiles could be joined alongone edge, with that edge sewn to the back of the seat mesh fabric. Theopposite edge would be joined with an elastic cord to combine the tilesinto a louver. The entire chain of rigid tiles would be swung againstthe mesh to close, or away from the mesh to open, flexing to match thecurvature of the seated passenger's back.

The number of louvers possible is a function of the thickness of thelouvers. If the louvers are paper-thin, then there can be a great manysmall louvers. For louvers with an appreciable thickness, there is alimit on the number of louvers because the thickness of each louverobstructs some airflow in the open state. In one implementation, theseat back thickness limits the louver width to slightly more than 1inch, allowing about 16 louvers per seat back. The seat bottom allowslouvers up to 2 inches deep, allowing about eight louvers. The louversneed not have a consistent thickness: a louver which was thin at thebase and thicker away from the seat mesh fabric would be more efficientin cooling mode than a louver of continuous thickness.

In accordance with an alternative embodiment, the suspension fabric seenin FIGS. 7 and 8 can be replaced by a rigid perforated material,including plastic or metal, or can even be a conventional foam cushionfitted with large channels or tubes to allow air to flow through thecushion.

Alternatively, the passenger supporting surface may include porous orperforated cushions made of spring-like materials, such as those usedfor some mattresses and sofas, provided that sufficient air to flowthrough the cushion from back to front.

Instead of strings or cords, the closing/opening mechanism may consistof a sheet of porous material attached to the louvers (or panels), suchthat when this sheet of fabric is moved parallel to the seated surfaceit pulls the louvers (or panels) from an open state to a closed stateand back.

In accordance with the further alternative embodiment shown in FIGS. 10Aand 10B, the passenger support surface 30 could be a substrate made of anon-porous (i.e., air-impermeable) material having high thermalconductivity, such that when airflow is constrained from flowing acrossthe back of support surface 30 by closed louvers 34 (see FIG. 10A), heattransfer from the support surface 30 into the ambient atmosphere isobstructed. Conversely, when the louvers 34 are open (see FIG. 10B),heat transfer into the ambient atmosphere is not obstructed.

High-thermal-conductivity material can also be used when the supportsurface is air-permeable. For example, highly thermally conductiveelements can be incorporated in a support surface comprising mesh fabricand/or the louvers to enhance heat transfer when the louvers are in theopen state. This could consist, for example, of highly thermallyconductive fibers (like woven copper or woven carbon mesh) incorporatedinto (i.e., integrated with) the seat mesh fabric and the face of thelouvers that folds towards the seat mesh. Thus, when the louvers areopen, the highly thermally conductive fibers conduct heat to the openface of the louvers and this cools the seated passenger; and when thelouvers are closed, the highly thermally conductive fibers on thelouvers are folded back onto themselves, against the seat mesh fabric,and are not exposed to air movement, and the passenger is not cooled bythe conductive fibers.

Another option would be to incorporate highly thermally conductivefibers into the seat mesh fabric itself, such that fibers on one surfaceare in contact with the seated passenger's back, and on the other sidethey are exposed to free air when the louvers are open, and not exposedto free air when the louvers are closed.

Suitable highly thermally conductive materials preferably have a thermalconductivity of at least 40 W/m-^(o)K. However, the shape of thehigh-thermal-conductivity material matters as much as the thermalconductivity in the overall heat transfer equation of the body to theambient atmosphere. In accordance with one embodiment, thermal heat sinkcompounds made of silicon rubber compounds that conduct heat better thansteel and also provide an elastic conformability could be used as seatmaterial.

Instead of louvers, airflow to and/or heat transfer from a passengersupport surface 30 (either air-permeable or non-porous) can becontrolled by a non-porous movable surface 36 disposed parallel to thesupport surface 30, as seen in FIGS. 11A and 11B. For example, thenon-porous movable surface 36 may take the form of a foam cushion placedbeneath or behind the support surface 30. In the cooling mode shown inFIG. 11A, the nonporous movable surface 36 is spaced apart from thesupport surface 30. In response to the seated passenger's selection ofthe heating mode, an actuator 38 presses the non-porous movable surface36 against the back of the support surface 30, as shown in FIG. 11B. Fora movable panel, the actuator may comprise a four-bar linkage or cam tolift the movable panel close to the support surface,

In accordance with a further embodiment, the movable surface make takethe form of a fabric sling 50 draped under and behind a support frame200 as partially depicted in FIG. 14. The fabric sling 50 may comprise asheet of fabric which is insulating (i.e., when support surface 30 hashigh thermal conductivity) and/or impervious to airflow (i.e., whensupport surface 30 is pervious to airflow). One end of the fabric sling50 can be secured to an upper portion (not shown) of the support frame200; the other end of fabric sling 50 is attached to and wound around arotatable cylinder 54. A portion of the fabric sling 50 passes over asecond rotatable cylinder 52 as the sling is wound onto or paid out fromthe rotatable cylinder 54. In this embodiment, a suspension fabric 220spans an opening in the support frame 200. In the heating mode, thefabric sling 50 can be tensioned into contact with the suspension fabric220 by rotating the rotating cylinder 54 in the direction indicated bythe arrow in FIG. 14. (The spacing between suspension fabric 220 andfabric sling 50 is provided for the purpose of clarity so that thedashed and solid lines do not contact each other, which contact wouldobscure the representation of separate fabrics.) Conversely, in order toswitch from the heating mode to the cooling mode, the rotating cylinder54 can be rotated in the opposite direction from that indicated by thearrow in FIG. 14. In that event, the fabric sling would become slack andfall away from the suspension fabric 220, as indicated by a series ofstraight arrows in FIG. 14. The fabric sling 50 may comprise wovenfabric or felt.

Alternatively, the fabric sling could carry a substrate (e.g., a foamcushion) which is pressed against the underside of the suspension fabricwhen the fabric sling is tensioned.

In accordance with a further alternative embodiment, a bladder or bagcould be devised to expand as cabin pressure changes, thereby pressingan impervious surface against the bottom or back of a suspension fabricor other type of porous substrate, thereby obstructing airflow throughthe pervious substrate.

In accordance with further embodiments, airflow and/or heat transfer canbe controlled by enclosing the space under or behind a suitablesupporting surface which is pervious or has high thermal conductivity,such that the enclosed space is opened to airflow or constrained fromallowing airflow by actuation of variable thermal resistance device. Forexample, FIG. 12 shows a space 40 behind a support surface 30, whichspace 40 can be enclosed by a variable thermal resistance device in theform of a stretchable sheet 42 whose porosity increases when stretched,e.g., by rotating a rotatable cylinder 44.

FIG. 13 shows a plan view of an embodiment in which the stretchablesheet 42 has an array of parallel, equally spaced slits 46. When one endof stretchable sheet 42 is pulled in the direction of the arrow whilethe other end is fixed, the stretchable sheet 42 will stretch, causingthe slits 46 to open (they are shown closed in FIG. 13).

In accordance with a variation of the embodiment shown in FIGS. 12 and13, the stretchable sheet may comprise numerous small staggered slitsclosely spaced such that when the sheet is in tension along the axis ofthe slits, the sheet is impermeable, but when tension is appliedperpendicular to the axis of the slits (or shear is applied to thesheet), the slits open and ventilate e the support surface.

In accordance with an alternative embodiment shown in FIGS. 16A and 16B,the seat back cover 60 can be provided with vents 64 and 66 that openand close. When the vents are closed as shown in FIG. 16A, the space 62between the back cover 60 and an air-permeable back support surface 12,which is heated by the passenger's body, would be enclosed. In contrast,when the vents 64, 66 in the back cover 60 are opened, cool air canenter the enclosed space 62 via vent 64 and the warm air inside theenclosed space 62 can exit via the vent 66 (this air flow is indicatedby arrows in FIG. 16B), thereby cooling the seated passenger. The ventsmay be coupled so that they move in tandem in response to manualrotation of a knob mounted on one side of the passenger seat or pressingof a switch that turns on a motor.

In accordance with other embodiments, the actuating mechanism mightcomprise a motor, which would switch the variable thermal resistancedevice from a heating mode to a cooling mode and back automatically asdirected by an electronic controller, or as directed by a switch on theseat, operated by the seat occupant.

In accordance with a further alternative embodiment, the actuatingmechanism may comprise a thermally activated device (for example, abimaterial or shape memory alloy actuator) which would switch thevariable thermal resistance device from a heating mode to a cooling modeand back automatically as the cabin temperature changed. Optionally, theactuating mechanism might comprise a pressure-operated device (forexample, a bellows, piston or bladder) which would switch the seat fromheating mode to cooling mode and back automatically as the cabinpressure changed.

If an airline were to decide to have all the variable thermal resistancedevices be resettable to (for example) a fully open position after thearriving passengers leave and before the next group of passengersarrive, maintenance time would be required to reset the seats which arenot remotely resettable electronically. This could be resolved with theaddition of a spring-actuated device that would reset the seat to thefully open position when the passenger rises from the seat. The airlinewould have to balance the added weight, complexity, and increasedfailure rate caused by a spring-loaded return mechanism versus theeffort to manually reset the seats as they are being cleaned betweenflights.

Alternatively, in cases wherein the variable thermal resistance devicesare actuated by electronic motors, all the variable thermal resistancedevices could be remotely resettable electronically. For example, FIG.15 is a block diagram showing components of an electronically controlledsystem for varying the thermal resistance of passenger seats of avehicle. Components for only two seats are shown. Seat No. 1 comprises avariable thermal resistance assembly 88 which can be actuated by a motor86 in response to the passenger seated in Seat No. 1 pressing a switch80 located on an armrest; similarly, Seat No. 2 comprises a variablethermal resistance assembly 92 which can be actuated by a motor 90 inresponse to the passenger seated in Seat No. 2 pressing a switch 82located on an armrest. Alternatively, a flight crew member could actuateboth motors 86 and 90 remotely using an electronic controller 84. Theelectronic controller 84 can be programmed to reset all variable thermalresistance assemblies in sequence or in groups in response to the inputof a command via a user interface (not shown).

While the invention has been described with reference to variousembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationto the teachings herein without departing from the essential scopethereof. Therefore it is intended that the claims not be limited to theparticular embodiments disclosed.

As used in the claims, the term “support surface” refers to a substratecapable of supporting weight. A support surface can be either porous(i.e., air-permeable) or non-porous. Similarly, as used in the claims,the term “movable surface” refers to a substrate which is movable. Asused herein, the term “substrate” encompasses at least the following: asheet (plastic or metal), a layer of foam, woven or non-woven fabric,webbing, or a mesh.

1. A seating assembly comprising: a frame having an opening; anair-permeable support surface spanning said opening in said frame; anair-impermeable back cover attached to said frame, said back cover andsaid support surface defining a space; and venting means incorporated insaid back cover, wherein ambient air is free to flow into and out ofsaid space via said venting means when said venting means are open, andambient air cannot enter said space via said venting means when saidventing means are closed.
 2. The seating assembly as recited in claim 1,wherein said air-permeable support surface comprises suspension fabric.3. The seating assembly as recited in claim 1, further comprising meansfor actuating said venting means to change state from closed to open. 4.The seating assembly as recited in claim 1, wherein said venting meanscomprise a first vent in an upper portion of said back cover and asecond vent in a lower portion of said back cover.
 5. The seatingassembly as recited in claim 4, further comprising first and secondactuators for actuating said first and second vents respectively tochange state from closed to open.
 6. The seating assembly as recited inclaim 4, wherein said first and second actuators are thermally activateddevices.
 7. The seating assembly as recited in claim 4, wherein saidfirst and second actuators are pressure-operated devices.
 8. The seatingassembly as recited in claim 4, wherein said first and second actuatorsare motors.
 9. The seating assembly as recited in claim 8, furthercomprising an electronic controller programmed to control said motors toopen said first and second vents in response to input of a command via auser interface.
 10. A seating assembly comprising: a structural frame;first and second movable frames movably coupled to and supported by saidstructural frame, said first movable frame comprising a first openingand said second movable frame comprising a second opening; first andsecond air-permeable support surfaces respectively spanning said firstand second openings in said first and second movable frames; a firstvariable thermal resistance device that opposes said first supportsurface when said first variable thermal resistance device is in aclosed state in which airflow is obstructed, said first variable thermalresistance device being movable from its closed state to an open statein which airflow is not obstructed and from its open state to its closedstate; a second variable thermal resistance device that opposes saidsecond support surface when said second variable thermal resistancedevice is in a closed state in which airflow is obstructed, said secondvariable thermal resistance device being movable from its closed stateto an open state in which airflow is not obstructed and from its openstate to its closed state; first and second motors coupled to said firstand second variable thermal resistance devices respectively, said firstand second motors being operable to actuate movement of said first andsecond variable thermal resistance devices respectively between saidopen and closed states; and an electronic controller programmed tocontrol said motors to move said first and second variable thermalresistance devices into their open states in response to input of acommand via a user interface when said first and second variable thermalresistance devices are in their closed states.
 11. The seating assemblyas recited in claim 10, wherein said first variable thermal resistancedevice comprises an air-impermeable back cover having first and secondvents which open or close in response to operation of said first motor.12. The seating assembly as recited in claim 10, wherein said firstvariable thermal resistance device comprises a multiplicity of louverscoupled to said first air-permeable support surface.
 13. The seatingassembly as recited in claim 10, wherein said first variable thermalresistance device comprises a movable surface that is movable between anopen position not in contact with said first air-permeable supportsurface and a closed position in contact with said first air-permeablesupport surface in response to actuation of said first motor.
 14. Theseating assembly as recited in claim 13, wherein said movable surfacecomprises a sling made of fabric or felt, said sling being slack and outof contact with said first air-permeable support surface when said firstmotor is in a first state and under tension and in contact with saidfirst air-permeable support surface when said first motor is in a secondstate.
 15. A seating assembly comprising: a frame having an opening; anair-permeable support surface spanning said opening in said frame; anair-impermeable back cover attached to said frame, said back cover andsaid support surface defining a space; a first vent in an upper portionof said back cover; a first actuator coupled to said first vent, saidfirst actuator being operable to change a state of said first vent fromeither open to closed or from closed to open; a second vent in a lowerportion of said back cover; and a second actuator coupled to said secondvent, said second actuator being operable to change a state of saidsecond vent from either open to closed or from closed to open, whereinambient air is free to flow into and out of said space via said firstand second vents means when said first and second vents are open, andambient air cannot enter said space via said first and second vents whensaid first and second vents are closed.
 16. The seating assembly asrecited in claim 15, wherein said first and second actuators arethermally activated devices.
 17. The seating assembly as recited inclaim 15, wherein said first and second actuators are pressure-operateddevices.
 18. The seating assembly as recited in claim 15, wherein saidfirst and second actuators are motors.
 19. The seating assembly asrecited in claim 18, further comprising an electronic controllerprogrammed to control said motors to open said first and second vents inresponse to input of a command via a user interface.
 20. The seatingassembly as recited in claim 15, wherein said air-permeable supportsurface comprises suspension fabric.